High-Intensity Focused Ultrasound Surgery for Tumor Ablation: A Review of Current Applications

The management of cancer with alternative approaches is a matter of clinical interest worldwide. High-intensity focused ultrasound (HIFU) surgery is a noninvasive technique performed under US or MRI guidance. The most studied therapeutic uses of HIFU involve thermal tissue ablation, demonstrating both palliative and curative potential. However, concurrent mechanical bioeffects also provide opportunities in terms of augmented drug delivery and immunosensitization. The safety and efficacy of HIFU integration with current cancer treatment strategies are being actively investigated in managing primary and secondary tumors, including cancers of the breast, prostate, pancreas, liver, kidney, and bone. Current primary HIFU indications are pain palliation, complete ablation of localized earlystage tumors, or debulking of unresectable late-stage cancers. This review presents the latest HIFU applications, from investigational to clinically approved, in the field of tumor ablation. Keywords: Ultrasound, Ultrasound-High Intensity Focused (HIFU), Interventional-MSK, Interventional-Body, Oncology, Technology Assessment, Tumor Response, MR Imaging © RSNA, 2023.

Automated Morphometric Analysis of the Hip Joint on MRI from the German National Cohort Study

Purpose

To develop and validate an automated morphometric analysis framework for the quantitative analysis of geometric hip joint parameters in MR images from the German National Cohort (GNC) study.

Materials and Methods

A secondary analysis on 40 participants (mean age, 51 years; age range, 30-67 years; 25 women) from the prospective GNC MRI study (2015-2016) was performed. Based on a proton density-weighted three-dimensional fast spin-echo sequence, a morphometric analysis approach was developed, including deep learning-based landmark localization, bone segmentation of the femora and pelvis, and a shape model for annotation transfer. The centrum-collum-diaphyseal, center-edge (CE), three alpha angles, head-neck offset (HNO), and HNO ratio along with the acetabular depth, inclination, and anteversion were derived. Quantitative validation was provided by comparison with average manual assessments of radiologists in a cross-validation format. Paired-sample t tests with a Bonferroni-corrected significance level of .005 were employed alongside mean differences and 10th/90th percentiles, median absolute deviations (MADs), and intraclass correlation coefficients (ICCs).

Results

High agreement in mean Dice similarity coefficients was achieved (average of 97.52% ± 0.46 [standard deviation]). The subsequent morphometric analysis produced results with low mean MAD values, with the highest values of 3.34° (alpha 03:00 o'clock position) and 0.87 mm (HNO) and ICC values ranging between 0.288 (HNO ratio) and 0.858 (CE) compared with manual assessments. These values were in line with interreader agreements, which at most had MAD values of 4.02° (alpha 12:00 o'clock position) and 1.07 mm (HNO) and ICC values ranging between 0.218 (HNO ratio) and 0.777 (CE).

Conclusion

Automatic extraction of geometric hip parameters from MRI is feasible using a morphometric analysis approach with deep learning.Keywords: Computer-Aided Diagnosis (CAD), Interventional-MSK, MR-Imaging, Neural Networks, Skeletal-Appendicular, Hip, Anatomy, Computer Applications-3D, Segmentation, Vision, Application Domain, Quantification Supplemental material is available for this article. © RSNA, 2021.

Combined Angio-CT Systems: A Roadmap Tool for Precision Therapy in Interventional Oncology

Combined angiography-CT (angio-CT) systems, which combine traditional angiographic imaging with cross-sectional imaging, are a valuable tool for interventional radiology. Although cone-beam CT (CBCT) technology from flat-panel angiography systems has been established as an adjunct cross-sectional imaging tool during interventional procedures, the intrinsic advantages of angio-CT systems concerning superior soft-tissue imaging and contrast resolution, along with operational ease, have sparked renewed interest in their use in interventional oncology procedures. Owing to increases in affordability and usability due to an improved workflow, angio-CT systems have become a viable alternative to stand-alone flat-panel angiographic systems equipped with CBCT. This review aims to provide a comprehensive technical and clinical guide for the use of angio-CT systems in interventional oncology. The basic concepts related to the use of angio-CT systems, including concepts related to workflow setup, imaging characteristics, and acquisition parameters, will be discussed. Additionally, an overview on the clinical applications and the benefits of angio-CT systems in routine therapeutic and palliative interventional oncology procedures will be reviewed. Keywords: Ablation Techniques, CT-Angiography, Interventional-Body, Interventional-MSK, Chemoembolization, Embolization, Radiation Therapy/Oncology, Abdomen/GI, Skeletal-Axial Supplemental material is available for this article. © RSNA, 2021.

Prophylactic Percutaneous Consolidation of Large Osteolytic Tumors of the Pelvic Ring Using Fixation by Internal Cemented Screws

Purpose To evaluate the efficacy, durability, and safety of percutaneous fixation by internal cemented screw (FICS) for prophylactic consolidation of impending pathologic fractures of the pelvic ring. Materials and Methods In this single-institute retrospective study, patients with large, minimally symptomatic to asymptomatic osteolytic tumors of the pelvic ring that were treated with percutaneous cone-beam CT-guided FICS procedures were included (January 2014 to May 2019). Follow-up cross-section imaging and clinical reports were reviewed for procedural complications and assessment of the long-term consolidation efficacy on the basis of the development of pathologic fracture or need for additional surgical intervention. All continuous variables were expressed as a mean with standard deviation, and dichotomous variables were expressed as frequencies and percentages. Results Fifty consecutive patients (mean age, 60 years ± 12; 27 men) underwent prophylactic FICS for consolidation of 54 osteolytic tumors (mean size, 51 mm ± 21.5; range, 30-114 mm). Local tumor destruction was performed in association with FICS in 38 patients (76%) using percutaneous thermal and/or radiation therapy. Follow-up exceeded a year in 35 patients (70%), with mean follow-up of 22 months ± 18 (range, 1-67 months). Long-term consolidation efficacy was 98% (49 of 50), with the development of a pathologic fracture in only one patient 20 months after FICS. Procedural complications were limited to two patients with self-resolving hematoma, one patient with inflammatory sciatic pain, and one patient with focal pain at the ischial tuberosity. Conclusion Percutaneous FICS provides a safe and durable minimally invasive treatment for the prevention of pathologic fractures of the pelvic ring. Keywords: Interventional-MSK, Percutaneous, Skeletal-Axial, Metastases, Oncology Supplemental material is available for this article. © RSNA, 2020.